The SAMI Galaxy Survey: embedded discs and radial trends in outer dynamical support across the Hubble sequence
Caroline Foster, J. van de Sande, L. Cortese, S. M. Croom, J. Bland-Hawthorn, S. Brough, J. J. Bryant, M. Goodwin, J. S. Lawrence, N. Lorente, A. M. Medling, M.… 展开作者
Caroline Foster, J. van de Sande, L. Cortese, S. M. Croom, J. Bland-Hawthorn, S. Brough, J. J. Bryant, M. Goodwin, J. S. Lawrence, N. Lorente, A. M. Medling, M. Owers, S. N. Richards, N. Scott
We study the balance in dynamical support of 384 galaxies with stellar kinematics out to >1.5R_e in the Sydney AAO Multi-object Integral Field (SAMI) Galaxy Survey. We present radial dynamical profiles of the local rotation dominance parameter, V/sigma, and local spin, lambda_loc. Although there is a broad range in amplitude, most kinematic profiles monotonically increase across the probed radial range. We do not find many galaxies with kinematic transitions such as those expected between the inner in-situ and outer accreted stars within the radial range probed. We compare the V/sigma gradient and maximum values to the visual morphologies of the galaxies to better understand the link between visual and kinematic morphologies. We find that the radial distribution of dynamical support in galaxies is linked to their visual morphology. Late-type systems have higher rotational support at all radii and steeper V/sigma gradients compared to early-type galaxies. We perform a search for embedded discs, which are rotationally supported discy structures embedded within large scale slowly or non-rotating structures. Visual inspection of the kinematics reveals at most three galaxies (out of 384) harbouring embedded discs. This is more than an order of magnitude fewer than the observed fraction in some local studies. Our tests suggest that this tension can be attributed to differences in the sample selection, spatial sampling and beam smearing due to seeing.
Kinematic scaling of thin and thick discs from SAMI to NewHorizon
Yonsei University（延世大学）；CSIRO Space & Astronomy（澳大利亚联邦科学与工业研究组织空间与天文部）；Australian National University（澳大利亚国立大学）；The University of Sydney（悉尼大学）；Institut d’Astrophysique de Paris, CNRS and Sorbonne Université（巴黎天体物理研究所，法国国家科学研究中心和索邦大学）；Kyung Hee University（庆熙大学）
该研究利用 SAMI 星系和 NewHorizon 模拟数据，通过施瓦兹席尔德轨道叠加等方法，重新审视盘状恒星质量与速度弥散关系并扩展到薄厚盘，揭示了相关结果及系统误差，为未来研究盘状子结构提供方向。
The SAMI Galaxy Survey: Gas velocity dispersions in low-$z$ star-forming galaxies and the drivers of turbulence
我们推断的内在电离气体运动学的383恒星形成星系在一个范围内的综合恒星形成率（SFR $\in [10^{-3}, 10^2]$ M $_\odot$年$^{-1}$）在$z \lesssim 0.1$使用一致的三维正演模拟技术。总样本是SAMI星系巡天和SAMO巡天的星系组合。对于典型的低$z$星系从SAMI星系巡天，我们发现的垂直速度色散（$σ_{v, z}$）是正相关的恒星形成率，恒星质量，HI气体质量和旋转速度的措施。最大的相关性是与恒星形成率表面密度（$Σ_\text{SFR}$）。使用总样本，我们发现$σ_{v, z}$在范围SFR $\in$ [ $10^{-3}$，1] M $_\odot$ yr $^{-1}$从$17\pm3$ km s $^{-1}$到$24\pm5$ km s $^{-1}$内缓慢增加，然后急剧增加到$σ_{v, z}$ $\sim 80$ km s $^{-1}$，对于SFR $\gtrsim 1$ M $_\odot$ yr $^{-1}$。这与最近的理论模型是一致的，该模型提出了由恒星形成反馈过程驱动的$σ_{v, z}$地板，在较高的SFR下，由气体通过圆盘的引力传输驱动的$σ_{v, z}$向上翻转。
